Clinical Usefulness of Arbekacin

Practical Synthesis from Streptomycin and Regioselective Partial Deprotections of (-)-(1R,2S,3R,4R,5S,6S)-1,3-Di(deamino)-1,3-diazido-2,5,6-tri-O-benzylstreptamine

We describe the gram-scale synthesis of (-)-(1R,2S,3R,4R,5S,6S)-1,3-di(diamino)-1,3-diazido-2,5,6-tri-O-benzylstreptamine from streptomycin by (i) hydrolysis of the two streptomycin guanidine residues, (ii) reprotection of the amines as azides, (iii) protection of all alcohols as benzyl ethers, and (iv) glycosidic bond cleavage with HCl in methanol. Protocols for regioselective monodebenzylation and regioselective reduction of a single azide in the product are also described, providing four optically pure building blocks for exploitation in novel aminoglycoside synthesis.

A mini-review: environmental and metabolic factors affecting aminoglycoside efficacy

Following the discovery of streptomycin from Streptomyces griseus in the 1940s by Selman Waksman and colleagues, aminoglycosides were first used to treat tuberculosis and then numerous derivatives have since been used to combat a wide variety of bacterial infections. These bactericidal antibiotics were used as first-line treatments for several decades but were largely replaced by ß-lactams and fluoroquinolones in the 1980s, although widespread emergence of antibiotic-resistance has led to renewed interest in aminoglycosides. The primary site of action for aminoglycosides is the 30 S ribosomal subunit where they disrupt protein translation, which contributes to widespread cellular damage through a number of secondary effects including rapid uptake of aminoglycosides via elevated proton-motive force (PMF), membrane damage and breakdown, oxidative stress, and hyperpolarisation of the membrane. Several factors associated with aminoglycoside entry have been shown to impact upon bacterial killing, and more recent work has revealed a complex relationship between metabolic states and the efficacy of different aminoglycosides. Hence, it is imperative to consider the environmental conditions and bacterial physiology and how this can impact upon aminoglycoside entry and potency. This mini-review seeks to discuss recent advances in this area and how this might affect the future use of aminoglycosides.

A Comparative Review on Current and Future Drug Targets Against Bacteria & Malaria

Long before the discovery of drugs like 'antibiotic and anti-parasitic drugs', the infectious diseases caused by pathogenic bacteria and parasites remain as one of the major causes of morbidity and mortality in developing and underdeveloped countries. The phenomenon by which the organism exerts resistance against two or more structurally unrelated drugs is called multidrug resistance (MDR) and its emergence has further complicated the treatment scenario of infectious diseases. Resistance towards the available set of treatment options and poor pipeline of novel drug development puts an alarming situation. A universal goal in the post-genomic era is to identify novel targets/drugs for various life-threatening diseases caused by such pathogens. This review is conceptualized in the backdrop of drug resistance in two major pathogens i.e. "Pseudomonas aeruginosa" and "Plasmodium falciparum". In this review, the available targets and key mechanisms of resistance of these pathogens have been discussed in detail. An attempt has also been made to analyze the common drug targets of bacteria and malaria parasite to overcome the current drug resistance scenario. The solution is also hypothesized in terms of a present pipeline of drugs and efforts made by scientific community.

SARS-CoV-2 entry inhibitors by dual targeting TMPRSS2 and ACE2: An in silico drug repurposing study

The coronavirus disease (COVID-19) is spreading between human populations mainly through nasal droplets. Currently, the vaccines have great hope, but it takes years for testing its efficacy in human. As there is no specific drug treatment available for COVID-19 pandemic, we explored in silico repurposing of drugs with dual inhibition properties by targeting transmembrane serine protease 2 (TMPRSS2) and human angiotensin-converting enzyme 2 (ACE2) from FDA-approved drugs. The TMPRSS2 and ACE2 dual inhibitors in COVID-19 would be a novel antiviral class of drugs called “entry inhibitors.” For this purpose, approximately 2800 US-FDA approved drugs were docked using a virtual docking tool with the targets TMPRSS2 and ACE2. The best-fit drugs were selected as per docking scores and visual outcomes. Later on, drugs were selected on the basis of molecular dynamics simulations. The drugs alvimopan, arbekacin, dequalinum, fleroxacin, lopinavir, and valrubicin were shortlisted by visual analysis and molecular dynamics simulations. Among these, lopinavir and valrubicin were found to be superior in terms of dual inhibition. Thus, lopinavir and valrubicin have the potential of dual-target inhibition whereby preventing SARS-CoV-2 entry to the host. For repurposing of these drugs, further screening in vitro and in vivo would help in exploring clinically.

In vitro activity of arbekacin against multidrug-resistant gram-negative bacilli

BACKGROUND

Arbekacin is a broad-spectrum aminoglycoside with activity against some Gram-positive and Gram-negative bacteria.

METHODS

Arbekacin minimum inhibitory concentration (MIC) values were determined for 296 drug-resistant Gram-negative bacilli, and compared to previously determined plazomicin, amikacin, gentamicin, and tobramycin MIC values.

RESULTS

The MIC values required to inhibit 50% and 90% of isolates (MIC₅₀ and MIC₉₀, respectively) were 16 and >128 μg/ml, respectively.

CONCLUSIONS

Arbekacin showed similar MIC₅₀ values to amikacin and gentamicin, a lower MIC₅₀ value than tobramycin, and a higher MIC₅₀ value than plazomicin.

Antibacterials in the pipeline and perspectives for the near future

Antimicrobial resistance is a global threat to the management of infections in our patients. Sound stewardship of antibacterial agents at our disposal must be accompanied by a concerted effort to develop new agents to bolster our armamentarium. This review will cover the latest antibiotics that have come through the pipeline and the role they can play in the management of infections that are increasingly difficult to treat due to resistance mechanisms.